Process of converting residues obtained on sweetening petroleum distillates



March 3, 1931. G. M. FISCHER 1,795,278

PROCESS OF CONVERTING RESIDUES OBTAINED ON SWEETENING PETROLEUM DI LLA'IES Filed'Aug. 25, 192

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i Lt u m V ijwoemtoz HERBERT 62M f'llscmsz Patented Mar. 3, 1931 v UNITED STATES PATENT OFFICE HERBERT G. M. FISCHER, OF WESTFIELD, NEW JERSEY, ASSIGNOR TO STANDARD OIL DEVELOPMENT COMPANY, A CORPORATION OF DELAWARE PROCESS OF CONVERTING RESIDUES OBTAINED ON SWEETENING PETROLEUM DISTILLATES Application filed August 25, 1927. Serial No. 215,302.

This invention relates to the treatment of certain residues obtained-on sweetening petroleum distillates and comprehends a process whereby such residues may be converted into more valuable products.

In accordance with a process which is shown in co-pending application, Serial No. 107,7 87, filed May 8, 1926, sour petroleum distillates are sweetened by contact with added sulfur and a catalyst, followed by distillation, preferably under reduced or sub-atmospheric pressure. This produces a sweetened distillate of low sulfur content and a residue oil containing the sulfur added and much of that originally present in the sour distillate. The sulfur in the residue oil is present mainly in the form of alkyl polysulfides, such as its etc.

, I have found that this residue oil may be converted by heat to an oil of reduced sulfur content, hydrogen sulfide, and hydrocarbon-sulfur compounds of lower boiling point than those originally present in the residue oil. The heat to be applied for this purpose 25. is in excess of 350 F., higher temperatures producing more rapid conversion. This conversion can be carried out by heating the residue oil in liquid and/or vapor phase and under pressure if desired.

If carried out under conditions such that a substantial part of the residue oil is vaporized, the hydrogen sulfide and hydrocarbonsulfur compounds formed will be found principally in the vaporized part and can he separated therefrom by fractionation. Al-

ternatively, the heating may be carried out under conditions such that relatively little of the residue oil is vaporized, but above 350 F. The mixture of hydrogen sulfide and hydrocarbon-sulfur compounds separates from the residue oil in vapor phase and are separated form each other by condensing the hydrocarbon-sulfur compounds from the mixture and conducting away the hydrogen sulfide gas.

of a series of tubes joined end to end to forma continuous circuit and is heated by gas burner 7 controlled by valves 8 and 9, as described below. The residue oil is preferably heated in the tubular heater to a temperature of 500 to 600 F. under a pressure which may range from 5 to lbs. gauge.

The oil flows from the tubular heater through pipe 10 and after passing pressure release valve 11 is discharged at atmospheri'c pressure into separator 12. A part vaporizes in'12, the vapors consisting principally of hydrogen sulfide and hydrocarbon-sulfur compounds of lower boiling point than those originally present in the residue oil. The vapors pass off through pipe 13 to condensing coil 14 supplied with cooling water from any suitable source. The products issuing from 14: through pipe 15 consist principally of liquid hydrocarbon-sulfur compounds and gaseous hydrogen sulfide, and separate in receptacle 16. The hydrogen sulfide passes off through pipe 17 and valve 9 to be introduced into the gas flowing to burner 7 through valve 8 and is thereby effectually disposed of. The liquid compounds are diverted through pipe 18 to cooler 19 and thereafter to any suitable accumulator.

The liquid separated in 12 flows through pipe 20 t0 the heat exchanger 2, in which it passes in indirect heat interchanging relationship to the residue oil being fed to the tubular heater, thence through cooler 21, and thereafter to any suitable accumulator.

It will be understood that the apparatus specifically shown is in illustration only and that my process may be carried out in various forms of apparatus. Various alternative procedures may be adopted within the scope of the appended claims, in which it is my intention to claim broadly all novelty inherent in my invention.

The term converting in the following claims is intended to mean the chemical transformation of the residue oil into an oil of reduced sulfur content, hydrogen sulfide, and hydrocarbon-sulfur compounds of lower boiling point than those originally present in the residue oil.

I claim:

1. The process of converting residue oil containing alkyl polysulfides and obtained by contacting sour petroleum distillates with sulfur in the presence of a catalyst followed by distillationunder sub-atmospheric pressure to produce a sweetened distillate and a residue oil, which comprises heating such residue oil to a temperature in excess of 350 F.

2. The process of converting residue oil containing alkyl polysulfides and obtained by contacting sour petroleum distillates with sulfur in the presence of a catalyst, followed by distillation under sub-atmospheric pressure to produce a sweetened distillate and a residue oil containing hydrocarbon-sulfur compounds, which comprises heating such residue oil to a temperature in excess of 350 F. to form hydrogen sulfide and hydrocarhon-sulfur compounds of lower boiling point than those originally present, thereafter sep-' arating the hydrogen sulfide and hydrocarbon-sulfur compounds formed from the residue oil.

3. The process of converting residue oil containing alkyl polysulfides and obtained by contacting sour petroleum distillates with sulfur in the presence of a catalyst, followed by distillation under sub-atmospheric pressure to produce a sweetened distillate and a residue oil containing hydrocarbon-sulfur compounds, which comprises heating such residue oil to a temperature in excess of 350 F., but below thetemperature of vaporization of a substantial part of the residue oil, to form a vapor comprising hydrogen sulfide and hydrocarbon-sulfur compounds of lower boiling point than those originally present, fractionally condensing from said mixture the hydrocarbon-sulfur compounds, and conducting away the hydrogen sulfide gas.

4. The process of converting residue o-il containing alkyl polysulfides and obtained by contacting sour petroleum distillates with sulfur in the presence of a catalyst, followed by distillation under sub-atmospheric pressure to produce a sweetened distillate and a residue oil containing hydrocarbon-sulfur compounds, which comprises flowing said residue oil in a continuous stream through a zone of heat for a period sufiicient to heat the 

